Fix flickering issues with low processor mode on Android

11 files changed, 2530 insertions, 23 deletions

diff --git a/platform/android/java/lib/src/org/godotengine/godot/GodotGLRenderView.java b/platform/android/java/lib/src/org/godotengine/godot/GodotGLRenderView.java
index 61093d54de..08da1b1832 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/GodotGLRenderView.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/GodotGLRenderView.java
@@ -29,6 +29,8 @@
 /*************************************************************************/
 
 package org.godotengine.godot;
+import org.godotengine.godot.gl.GLSurfaceView;
+import org.godotengine.godot.gl.GodotRenderer;
 import org.godotengine.godot.input.GodotGestureHandler;
 import org.godotengine.godot.input.GodotInputHandler;
 import org.godotengine.godot.utils.GLUtils;
@@ -43,7 +45,6 @@ import org.godotengine.godot.xr.regular.RegularFallbackConfigChooser;
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.graphics.PixelFormat;
-import android.opengl.GLSurfaceView;
 import android.os.Build;
 import android.view.GestureDetector;
 import android.view.KeyEvent;
diff --git a/platform/android/java/lib/src/org/godotengine/godot/GodotLib.java b/platform/android/java/lib/src/org/godotengine/godot/GodotLib.java
index 29e4b4b29e..253a51b83c 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/GodotLib.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/GodotLib.java
@@ -30,6 +30,8 @@
 
 package org.godotengine.godot;
 
+import org.godotengine.godot.gl.GodotRenderer;
+
 import android.app.Activity;
 import android.hardware.SensorEvent;
 import android.view.Surface;
@@ -68,7 +70,7 @@ public class GodotLib {
 	 * @param p_surface
 	 * @param p_width
 	 * @param p_height
-	 * @see android.opengl.GLSurfaceView.Renderer#onSurfaceChanged(GL10, int, int)
+	 * @see org.godotengine.godot.gl.GLSurfaceView.Renderer#onSurfaceChanged(GL10, int, int)
 	 */
 	public static native void resize(Surface p_surface, int p_width, int p_height);
 
@@ -85,9 +87,9 @@ public class GodotLib {
 
 	/**
 	 * Invoked on the GL thread to draw the current frame.
-	 * @see android.opengl.GLSurfaceView.Renderer#onDrawFrame(GL10)
+	 * @see org.godotengine.godot.gl.GLSurfaceView.Renderer#onDrawFrame(GL10)
 	 */
-	public static native void step();
+	public static native boolean step();
 
 	/**
 	 * Forward touch events from the main thread to the GL thread.
diff --git a/platform/android/java/lib/src/org/godotengine/godot/gl/EGLLogWrapper.java b/platform/android/java/lib/src/org/godotengine/godot/gl/EGLLogWrapper.java
new file mode 100644
index 0000000000..af16cfce74
--- /dev/null
+++ b/platform/android/java/lib/src/org/godotengine/godot/gl/EGLLogWrapper.java
@@ -0,0 +1,566 @@
+// clang-format off
+
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.godotengine.godot.gl;
+
+import android.opengl.GLDebugHelper;
+import android.opengl.GLException;
+
+import java.io.IOException;
+import java.io.Writer;
+
+import javax.microedition.khronos.egl.EGL;
+import javax.microedition.khronos.egl.EGL10;
+import javax.microedition.khronos.egl.EGL11;
+import javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.egl.EGLContext;
+import javax.microedition.khronos.egl.EGLDisplay;
+import javax.microedition.khronos.egl.EGLSurface;
+
+class EGLLogWrapper implements EGL11 {
+	private EGL10 mEgl10;
+	Writer mLog;
+	boolean mLogArgumentNames;
+	boolean mCheckError;
+	private int mArgCount;
+
+
+	public EGLLogWrapper(EGL egl, int configFlags, Writer log) {
+		mEgl10 = (EGL10) egl;
+		mLog = log;
+		mLogArgumentNames =
+				(GLDebugHelper.CONFIG_LOG_ARGUMENT_NAMES & configFlags) != 0;
+		mCheckError =
+				(GLDebugHelper.CONFIG_CHECK_GL_ERROR & configFlags) != 0;
+	}
+
+	public boolean eglChooseConfig(EGLDisplay display, int[] attrib_list,
+								   EGLConfig[] configs, int config_size, int[] num_config) {
+		begin("eglChooseConfig");
+		arg("display", display);
+		arg("attrib_list", attrib_list);
+		arg("config_size", config_size);
+		end();
+
+		boolean result = mEgl10.eglChooseConfig(display, attrib_list, configs,
+				config_size, num_config);
+		arg("configs", configs);
+		arg("num_config", num_config);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglCopyBuffers(EGLDisplay display, EGLSurface surface,
+								  Object native_pixmap) {
+		begin("eglCopyBuffers");
+		arg("display", display);
+		arg("surface", surface);
+		arg("native_pixmap", native_pixmap);
+		end();
+
+		boolean result = mEgl10.eglCopyBuffers(display, surface, native_pixmap);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public EGLContext eglCreateContext(EGLDisplay display, EGLConfig config,
+									   EGLContext share_context, int[] attrib_list) {
+		begin("eglCreateContext");
+		arg("display", display);
+		arg("config", config);
+		arg("share_context", share_context);
+		arg("attrib_list", attrib_list);
+		end();
+
+		EGLContext result = mEgl10.eglCreateContext(display, config,
+				share_context, attrib_list);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public EGLSurface eglCreatePbufferSurface(EGLDisplay display,
+											  EGLConfig config, int[] attrib_list) {
+		begin("eglCreatePbufferSurface");
+		arg("display", display);
+		arg("config", config);
+		arg("attrib_list", attrib_list);
+		end();
+
+		EGLSurface result = mEgl10.eglCreatePbufferSurface(display, config,
+				attrib_list);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public EGLSurface eglCreatePixmapSurface(EGLDisplay display,
+											 EGLConfig config, Object native_pixmap, int[] attrib_list) {
+		begin("eglCreatePixmapSurface");
+		arg("display", display);
+		arg("config", config);
+		arg("native_pixmap", native_pixmap);
+		arg("attrib_list", attrib_list);
+		end();
+
+		EGLSurface result = mEgl10.eglCreatePixmapSurface(display, config,
+				native_pixmap, attrib_list);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public EGLSurface eglCreateWindowSurface(EGLDisplay display,
+											 EGLConfig config, Object native_window, int[] attrib_list) {
+		begin("eglCreateWindowSurface");
+		arg("display", display);
+		arg("config", config);
+		arg("native_window", native_window);
+		arg("attrib_list", attrib_list);
+		end();
+
+		EGLSurface result = mEgl10.eglCreateWindowSurface(display, config,
+				native_window, attrib_list);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglDestroyContext(EGLDisplay display, EGLContext context) {
+		begin("eglDestroyContext");
+		arg("display", display);
+		arg("context", context);
+		end();
+
+		boolean result = mEgl10.eglDestroyContext(display, context);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglDestroySurface(EGLDisplay display, EGLSurface surface) {
+		begin("eglDestroySurface");
+		arg("display", display);
+		arg("surface", surface);
+		end();
+
+		boolean result = mEgl10.eglDestroySurface(display, surface);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglGetConfigAttrib(EGLDisplay display, EGLConfig config,
+									  int attribute, int[] value) {
+		begin("eglGetConfigAttrib");
+		arg("display", display);
+		arg("config", config);
+		arg("attribute", attribute);
+		end();
+		boolean result = mEgl10.eglGetConfigAttrib(display, config, attribute,
+				value);
+		arg("value", value);
+		returns(result);
+		checkError();
+		return false;
+	}
+
+	public boolean eglGetConfigs(EGLDisplay display, EGLConfig[] configs,
+								 int config_size, int[] num_config) {
+		begin("eglGetConfigs");
+		arg("display", display);
+		arg("config_size", config_size);
+		end();
+
+		boolean result = mEgl10.eglGetConfigs(display, configs, config_size,
+				num_config);
+		arg("configs", configs);
+		arg("num_config", num_config);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public EGLContext eglGetCurrentContext() {
+		begin("eglGetCurrentContext");
+		end();
+
+		EGLContext result = mEgl10.eglGetCurrentContext();
+		returns(result);
+
+		checkError();
+		return result;
+	}
+
+	public EGLDisplay eglGetCurrentDisplay() {
+		begin("eglGetCurrentDisplay");
+		end();
+
+		EGLDisplay result = mEgl10.eglGetCurrentDisplay();
+		returns(result);
+
+		checkError();
+		return result;
+	}
+
+	public EGLSurface eglGetCurrentSurface(int readdraw) {
+		begin("eglGetCurrentSurface");
+		arg("readdraw", readdraw);
+		end();
+
+		EGLSurface result = mEgl10.eglGetCurrentSurface(readdraw);
+		returns(result);
+
+		checkError();
+		return result;
+	}
+
+	public EGLDisplay eglGetDisplay(Object native_display) {
+		begin("eglGetDisplay");
+		arg("native_display", native_display);
+		end();
+
+		EGLDisplay result = mEgl10.eglGetDisplay(native_display);
+		returns(result);
+
+		checkError();
+		return result;
+	}
+
+	public int eglGetError() {
+		begin("eglGetError");
+		end();
+
+		int result = mEgl10.eglGetError();
+		returns(getErrorString(result));
+
+		return result;
+	}
+
+	public boolean eglInitialize(EGLDisplay display, int[] major_minor) {
+		begin("eglInitialize");
+		arg("display", display);
+		end();
+		boolean result = mEgl10.eglInitialize(display, major_minor);
+		returns(result);
+		arg("major_minor", major_minor);
+		checkError();
+		return result;
+	}
+
+	public boolean eglMakeCurrent(EGLDisplay display, EGLSurface draw,
+								  EGLSurface read, EGLContext context) {
+		begin("eglMakeCurrent");
+		arg("display", display);
+		arg("draw", draw);
+		arg("read", read);
+		arg("context", context);
+		end();
+		boolean result = mEgl10.eglMakeCurrent(display, draw, read, context);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglQueryContext(EGLDisplay display, EGLContext context,
+								   int attribute, int[] value) {
+		begin("eglQueryContext");
+		arg("display", display);
+		arg("context", context);
+		arg("attribute", attribute);
+		end();
+		boolean result = mEgl10.eglQueryContext(display, context, attribute,
+				value);
+		returns(value[0]);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public String eglQueryString(EGLDisplay display, int name) {
+		begin("eglQueryString");
+		arg("display", display);
+		arg("name", name);
+		end();
+		String result = mEgl10.eglQueryString(display, name);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglQuerySurface(EGLDisplay display, EGLSurface surface,
+								   int attribute, int[] value) {
+		begin("eglQuerySurface");
+		arg("display", display);
+		arg("surface", surface);
+		arg("attribute", attribute);
+		end();
+		boolean result = mEgl10.eglQuerySurface(display, surface, attribute,
+				value);
+		returns(value[0]);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglSwapBuffers(EGLDisplay display, EGLSurface surface) {
+		begin("eglSwapBuffers");
+		arg("display", display);
+		arg("surface", surface);
+		end();
+		boolean result = mEgl10.eglSwapBuffers(display, surface);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglTerminate(EGLDisplay display) {
+		begin("eglTerminate");
+		arg("display", display);
+		end();
+		boolean result = mEgl10.eglTerminate(display);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglWaitGL() {
+		begin("eglWaitGL");
+		end();
+		boolean result = mEgl10.eglWaitGL();
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	public boolean eglWaitNative(int engine, Object bindTarget) {
+		begin("eglWaitNative");
+		arg("engine", engine);
+		arg("bindTarget", bindTarget);
+		end();
+		boolean result = mEgl10.eglWaitNative(engine, bindTarget);
+		returns(result);
+		checkError();
+		return result;
+	}
+
+	private void checkError() {
+		int eglError;
+		if ((eglError = mEgl10.eglGetError()) != EGL_SUCCESS) {
+			String errorMessage = "eglError: " + getErrorString(eglError);
+			logLine(errorMessage);
+			if (mCheckError) {
+				throw new GLException(eglError, errorMessage);
+			}
+		}
+	}
+
+	private void logLine(String message) {
+		log(message + '\n');
+	}
+
+	private void log(String message) {
+		try {
+			mLog.write(message);
+		} catch (IOException e) {
+			// Ignore exception, keep on trying
+		}
+	}
+
+	private void begin(String name) {
+		log(name + '(');
+		mArgCount = 0;
+	}
+
+	private void arg(String name, String value) {
+		if (mArgCount++ > 0) {
+			log(", ");
+		}
+		if (mLogArgumentNames) {
+			log(name + "=");
+		}
+		log(value);
+	}
+
+	private void end() {
+		log(");\n");
+		flush();
+	}
+
+	private void flush() {
+		try {
+			mLog.flush();
+		} catch (IOException e) {
+			mLog = null;
+		}
+	}
+
+	private void arg(String name, int value) {
+		arg(name, Integer.toString(value));
+	}
+
+	private void arg(String name, Object object) {
+		arg(name, toString(object));
+	}
+
+	private void arg(String name, EGLDisplay object) {
+		if (object == EGL10.EGL_DEFAULT_DISPLAY) {
+			arg(name, "EGL10.EGL_DEFAULT_DISPLAY");
+		} else if (object == EGL_NO_DISPLAY) {
+			arg(name, "EGL10.EGL_NO_DISPLAY");
+		} else {
+			arg(name, toString(object));
+		}
+	}
+
+	private void arg(String name, EGLContext object) {
+		if (object == EGL10.EGL_NO_CONTEXT) {
+			arg(name, "EGL10.EGL_NO_CONTEXT");
+		} else {
+			arg(name, toString(object));
+		}
+	}
+
+	private void arg(String name, EGLSurface object) {
+		if (object == EGL10.EGL_NO_SURFACE) {
+			arg(name, "EGL10.EGL_NO_SURFACE");
+		} else {
+			arg(name, toString(object));
+		}
+	}
+
+	private void returns(String result) {
+		log(" returns " + result + ";\n");
+		flush();
+	}
+
+	private void returns(int result) {
+		returns(Integer.toString(result));
+	}
+
+	private void returns(boolean result) {
+		returns(Boolean.toString(result));
+	}
+
+	private void returns(Object result) {
+		returns(toString(result));
+	}
+
+	private String toString(Object obj) {
+		if (obj == null) {
+			return "null";
+		} else {
+			return obj.toString();
+		}
+	}
+
+	private void arg(String name, int[] arr) {
+		if (arr == null) {
+			arg(name, "null");
+		} else {
+			arg(name, toString(arr.length, arr, 0));
+		}
+	}
+
+	private void arg(String name, Object[] arr) {
+		if (arr == null) {
+			arg(name, "null");
+		} else {
+			arg(name, toString(arr.length, arr, 0));
+		}
+	}
+
+	private String toString(int n, int[] arr, int offset) {
+		StringBuilder buf = new StringBuilder();
+		buf.append("{\n");
+		int arrLen = arr.length;
+		for (int i = 0; i < n; i++) {
+			int index = offset + i;
+			buf.append(" [" + index + "] = ");
+			if (index < 0 || index >= arrLen) {
+				buf.append("out of bounds");
+			} else {
+				buf.append(arr[index]);
+			}
+			buf.append('\n');
+		}
+		buf.append("}");
+		return buf.toString();
+	}
+
+	private String toString(int n, Object[] arr, int offset) {
+		StringBuilder buf = new StringBuilder();
+		buf.append("{\n");
+		int arrLen = arr.length;
+		for (int i = 0; i < n; i++) {
+			int index = offset + i;
+			buf.append(" [" + index + "] = ");
+			if (index < 0 || index >= arrLen) {
+				buf.append("out of bounds");
+			} else {
+				buf.append(arr[index]);
+			}
+			buf.append('\n');
+		}
+		buf.append("}");
+		return buf.toString();
+	}
+
+	private static String getHex(int value) {
+		return "0x" + Integer.toHexString(value);
+	}
+
+	public static String getErrorString(int error) {
+		switch (error) {
+			case EGL_SUCCESS:
+				return "EGL_SUCCESS";
+			case EGL_NOT_INITIALIZED:
+				return "EGL_NOT_INITIALIZED";
+			case EGL_BAD_ACCESS:
+				return "EGL_BAD_ACCESS";
+			case EGL_BAD_ALLOC:
+				return "EGL_BAD_ALLOC";
+			case EGL_BAD_ATTRIBUTE:
+				return "EGL_BAD_ATTRIBUTE";
+			case EGL_BAD_CONFIG:
+				return "EGL_BAD_CONFIG";
+			case EGL_BAD_CONTEXT:
+				return "EGL_BAD_CONTEXT";
+			case EGL_BAD_CURRENT_SURFACE:
+				return "EGL_BAD_CURRENT_SURFACE";
+			case EGL_BAD_DISPLAY:
+				return "EGL_BAD_DISPLAY";
+			case EGL_BAD_MATCH:
+				return "EGL_BAD_MATCH";
+			case EGL_BAD_NATIVE_PIXMAP:
+				return "EGL_BAD_NATIVE_PIXMAP";
+			case EGL_BAD_NATIVE_WINDOW:
+				return "EGL_BAD_NATIVE_WINDOW";
+			case EGL_BAD_PARAMETER:
+				return "EGL_BAD_PARAMETER";
+			case EGL_BAD_SURFACE:
+				return "EGL_BAD_SURFACE";
+			case EGL11.EGL_CONTEXT_LOST:
+				return "EGL_CONTEXT_LOST";
+			default:
+				return getHex(error);
+		}
+	}
+}
diff --git a/platform/android/java/lib/src/org/godotengine/godot/gl/GLSurfaceView.java b/platform/android/java/lib/src/org/godotengine/godot/gl/GLSurfaceView.java
new file mode 100644
index 0000000000..8449c08b88
--- /dev/null
+++ b/platform/android/java/lib/src/org/godotengine/godot/gl/GLSurfaceView.java
@@ -0,0 +1,1939 @@
+// clang-format off
+
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.godotengine.godot.gl;
+
+import android.content.Context;
+import android.opengl.EGL14;
+import android.opengl.EGLExt;
+import android.opengl.GLDebugHelper;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.SurfaceHolder;
+import android.view.SurfaceView;
+
+import java.io.Writer;
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+
+import javax.microedition.khronos.egl.EGL10;
+import javax.microedition.khronos.egl.EGL11;
+import javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.egl.EGLContext;
+import javax.microedition.khronos.egl.EGLDisplay;
+import javax.microedition.khronos.egl.EGLSurface;
+import javax.microedition.khronos.opengles.GL;
+import javax.microedition.khronos.opengles.GL10;
+
+/**
+ * An implementation of SurfaceView that uses the dedicated surface for
+ * displaying OpenGL rendering.
+ * <p>
+ * A GLSurfaceView provides the following features:
+ * <p>
+ * <ul>
+ * <li>Manages a surface, which is a special piece of memory that can be
+ * composited into the Android view system.
+ * <li>Manages an EGL display, which enables OpenGL to render into a surface.
+ * <li>Accepts a user-provided Renderer object that does the actual rendering.
+ * <li>Renders on a dedicated thread to decouple rendering performance from the
+ * UI thread.
+ * <li>Supports both on-demand and continuous rendering.
+ * <li>Optionally wraps, traces, and/or error-checks the renderer's OpenGL calls.
+ * </ul>
+ *
+ * <div class="special reference">
+ * <h3>Developer Guides</h3>
+ * <p>For more information about how to use OpenGL, read the
+ * <a href="{@docRoot}guide/topics/graphics/opengl.html">OpenGL</a> developer guide.</p>
+ * </div>
+ *
+ * <h3>Using GLSurfaceView</h3>
+ * <p>
+ * Typically you use GLSurfaceView by subclassing it and overriding one or more of the
+ * View system input event methods. If your application does not need to override event
+ * methods then GLSurfaceView can be used as-is. For the most part
+ * GLSurfaceView behavior is customized by calling "set" methods rather than by subclassing.
+ * For example, unlike a regular View, drawing is delegated to a separate Renderer object which
+ * is registered with the GLSurfaceView
+ * using the {@link #setRenderer(Renderer)} call.
+ * <p>
+ * <h3>Initializing GLSurfaceView</h3>
+ * All you have to do to initialize a GLSurfaceView is call {@link #setRenderer(Renderer)}.
+ * However, if desired, you can modify the default behavior of GLSurfaceView by calling one or
+ * more of these methods before calling setRenderer:
+ * <ul>
+ * <li>{@link #setDebugFlags(int)}
+ * <li>{@link #setEGLConfigChooser(boolean)}
+ * <li>{@link #setEGLConfigChooser(EGLConfigChooser)}
+ * <li>{@link #setEGLConfigChooser(int, int, int, int, int, int)}
+ * <li>{@link #setGLWrapper(GLWrapper)}
+ * </ul>
+ * <p>
+ * <h4>Specifying the android.view.Surface</h4>
+ * By default GLSurfaceView will create a PixelFormat.RGB_888 format surface. If a translucent
+ * surface is required, call getHolder().setFormat(PixelFormat.TRANSLUCENT).
+ * The exact format of a TRANSLUCENT surface is device dependent, but it will be
+ * a 32-bit-per-pixel surface with 8 bits per component.
+ * <p>
+ * <h4>Choosing an EGL Configuration</h4>
+ * A given Android device may support multiple EGLConfig rendering configurations.
+ * The available configurations may differ in how many channels of data are present, as
+ * well as how many bits are allocated to each channel. Therefore, the first thing
+ * GLSurfaceView has to do when starting to render is choose what EGLConfig to use.
+ * <p>
+ * By default GLSurfaceView chooses a EGLConfig that has an RGB_888 pixel format,
+ * with at least a 16-bit depth buffer and no stencil.
+ * <p>
+ * If you would prefer a different EGLConfig
+ * you can override the default behavior by calling one of the
+ * setEGLConfigChooser methods.
+ * <p>
+ * <h4>Debug Behavior</h4>
+ * You can optionally modify the behavior of GLSurfaceView by calling
+ * one or more of the debugging methods {@link #setDebugFlags(int)},
+ * and {@link #setGLWrapper}. These methods may be called before and/or after setRenderer, but
+ * typically they are called before setRenderer so that they take effect immediately.
+ * <p>
+ * <h4>Setting a Renderer</h4>
+ * Finally, you must call {@link #setRenderer} to register a {@link Renderer}.
+ * The renderer is
+ * responsible for doing the actual OpenGL rendering.
+ * <p>
+ * <h3>Rendering Mode</h3>
+ * Once the renderer is set, you can control whether the renderer draws
+ * continuously or on-demand by calling
+ * {@link #setRenderMode}. The default is continuous rendering.
+ * <p>
+ * <h3>Activity Life-cycle</h3>
+ * A GLSurfaceView must be notified when to pause and resume rendering. GLSurfaceView clients
+ * are required to call {@link #onPause()} when the activity stops and
+ * {@link #onResume()} when the activity starts. These calls allow GLSurfaceView to
+ * pause and resume the rendering thread, and also allow GLSurfaceView to release and recreate
+ * the OpenGL display.
+ * <p>
+ * <h3>Handling events</h3>
+ * <p>
+ * To handle an event you will typically subclass GLSurfaceView and override the
+ * appropriate method, just as you would with any other View. However, when handling
+ * the event, you may need to communicate with the Renderer object
+ * that's running in the rendering thread. You can do this using any
+ * standard Java cross-thread communication mechanism. In addition,
+ * one relatively easy way to communicate with your renderer is
+ * to call
+ * {@link #queueEvent(Runnable)}. For example:
+ * <pre class="prettyprint">
+ * class MyGLSurfaceView extends GLSurfaceView {
+ *
+ *     private MyRenderer mMyRenderer;
+ *
+ *     public void start() {
+ *         mMyRenderer = ...;
+ *         setRenderer(mMyRenderer);
+ *     }
+ *
+ *     public boolean onKeyDown(int keyCode, KeyEvent event) {
+ *         if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
+ *             queueEvent(new Runnable() {
+ *                 // This method will be called on the rendering
+ *                 // thread:
+ *                 public void run() {
+ *                     mMyRenderer.handleDpadCenter();
+ *                 }});
+ *             return true;
+ *         }
+ *         return super.onKeyDown(keyCode, event);
+ *     }
+ * }
+ * </pre>
+ *
+ */
+public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback2 {
+	private final static String TAG = "GLSurfaceView";
+	private final static boolean LOG_ATTACH_DETACH = false;
+	private final static boolean LOG_THREADS = false;
+	private final static boolean LOG_PAUSE_RESUME = false;
+	private final static boolean LOG_SURFACE = false;
+	private final static boolean LOG_RENDERER = false;
+	private final static boolean LOG_RENDERER_DRAW_FRAME = false;
+	private final static boolean LOG_EGL = false;
+	/**
+	 * The renderer only renders
+	 * when the surface is created, or when {@link #requestRender} is called.
+	 *
+	 * @see #getRenderMode()
+	 * @see #setRenderMode(int)
+	 * @see #requestRender()
+	 */
+	public final static int RENDERMODE_WHEN_DIRTY = 0;
+	/**
+	 * The renderer is called
+	 * continuously to re-render the scene.
+	 *
+	 * @see #getRenderMode()
+	 * @see #setRenderMode(int)
+	 */
+	public final static int RENDERMODE_CONTINUOUSLY = 1;
+
+	/**
+	 * Check glError() after every GL call and throw an exception if glError indicates
+	 * that an error has occurred. This can be used to help track down which OpenGL ES call
+	 * is causing an error.
+	 *
+	 * @see #getDebugFlags
+	 * @see #setDebugFlags
+	 */
+	public final static int DEBUG_CHECK_GL_ERROR = 1;
+
+	/**
+	 * Log GL calls to the system log at "verbose" level with tag "GLSurfaceView".
+	 *
+	 * @see #getDebugFlags
+	 * @see #setDebugFlags
+	 */
+	public final static int DEBUG_LOG_GL_CALLS = 2;
+
+	/**
+	 * Standard View constructor. In order to render something, you
+	 * must call {@link #setRenderer} to register a renderer.
+	 */
+	public GLSurfaceView(Context context) {
+		super(context);
+		init();
+	}
+
+	/**
+	 * Standard View constructor. In order to render something, you
+	 * must call {@link #setRenderer} to register a renderer.
+	 */
+	public GLSurfaceView(Context context, AttributeSet attrs) {
+		super(context, attrs);
+		init();
+	}
+
+	@Override
+	protected void finalize() throws Throwable {
+		try {
+			if (mGLThread != null) {
+				// GLThread may still be running if this view was never
+				// attached to a window.
+				mGLThread.requestExitAndWait();
+			}
+		} finally {
+			super.finalize();
+		}
+	}
+
+	private void init() {
+		// Install a SurfaceHolder.Callback so we get notified when the
+		// underlying surface is created and destroyed
+		SurfaceHolder holder = getHolder();
+		holder.addCallback(this);
+		// setFormat is done by SurfaceView in SDK 2.3 and newer. Uncomment
+		// this statement if back-porting to 2.2 or older:
+		// holder.setFormat(PixelFormat.RGB_565);
+		//
+		// setType is not needed for SDK 2.0 or newer. Uncomment this
+		// statement if back-porting this code to older SDKs.
+		// holder.setType(SurfaceHolder.SURFACE_TYPE_GPU);
+	}
+
+	/**
+	 * Set the glWrapper. If the glWrapper is not null, its
+	 * {@link GLWrapper#wrap(GL)} method is called
+	 * whenever a surface is created. A GLWrapper can be used to wrap
+	 * the GL object that's passed to the renderer. Wrapping a GL
+	 * object enables examining and modifying the behavior of the
+	 * GL calls made by the renderer.
+	 * <p>
+	 * Wrapping is typically used for debugging purposes.
+	 * <p>
+	 * The default value is null.
+	 * @param glWrapper the new GLWrapper
+	 */
+	public void setGLWrapper(GLWrapper glWrapper) {
+		mGLWrapper = glWrapper;
+	}
+
+	/**
+	 * Set the debug flags to a new value. The value is
+	 * constructed by OR-together zero or more
+	 * of the DEBUG_CHECK_* constants. The debug flags take effect
+	 * whenever a surface is created. The default value is zero.
+	 * @param debugFlags the new debug flags
+	 * @see #DEBUG_CHECK_GL_ERROR
+	 * @see #DEBUG_LOG_GL_CALLS
+	 */
+	public void setDebugFlags(int debugFlags) {
+		mDebugFlags = debugFlags;
+	}
+
+	/**
+	 * Get the current value of the debug flags.
+	 * @return the current value of the debug flags.
+	 */
+	public int getDebugFlags() {
+		return mDebugFlags;
+	}
+
+	/**
+	 * Control whether the EGL context is preserved when the GLSurfaceView is paused and
+	 * resumed.
+	 * <p>
+	 * If set to true, then the EGL context may be preserved when the GLSurfaceView is paused.
+	 * <p>
+	 * Prior to API level 11, whether the EGL context is actually preserved or not
+	 * depends upon whether the Android device can support an arbitrary number of
+	 * EGL contexts or not. Devices that can only support a limited number of EGL
+	 * contexts must release the EGL context in order to allow multiple applications
+	 * to share the GPU.
+	 * <p>
+	 * If set to false, the EGL context will be released when the GLSurfaceView is paused,
+	 * and recreated when the GLSurfaceView is resumed.
+	 * <p>
+	 *
+	 * The default is false.
+	 *
+	 * @param preserveOnPause preserve the EGL context when paused
+	 */
+	public void setPreserveEGLContextOnPause(boolean preserveOnPause) {
+		mPreserveEGLContextOnPause = preserveOnPause;
+	}
+
+	/**
+	 * @return true if the EGL context will be preserved when paused
+	 */
+	public boolean getPreserveEGLContextOnPause() {
+		return mPreserveEGLContextOnPause;
+	}
+
+	/**
+	 * Set the renderer associated with this view. Also starts the thread that
+	 * will call the renderer, which in turn causes the rendering to start.
+	 * <p>This method should be called once and only once in the life-cycle of
+	 * a GLSurfaceView.
+	 * <p>The following GLSurfaceView methods can only be called <em>before</em>
+	 * setRenderer is called:
+	 * <ul>
+	 * <li>{@link #setEGLConfigChooser(boolean)}
+	 * <li>{@link #setEGLConfigChooser(EGLConfigChooser)}
+	 * <li>{@link #setEGLConfigChooser(int, int, int, int, int, int)}
+	 * </ul>
+	 * <p>
+	 * The following GLSurfaceView methods can only be called <em>after</em>
+	 * setRenderer is called:
+	 * <ul>
+	 * <li>{@link #getRenderMode()}
+	 * <li>{@link #onPause()}
+	 * <li>{@link #onResume()}
+	 * <li>{@link #queueEvent(Runnable)}
+	 * <li>{@link #requestRender()}
+	 * <li>{@link #setRenderMode(int)}
+	 * </ul>
+	 *
+	 * @param renderer the renderer to use to perform OpenGL drawing.
+	 */
+	public void setRenderer(Renderer renderer) {
+		checkRenderThreadState();
+		if (mEGLConfigChooser == null) {
+			mEGLConfigChooser = new SimpleEGLConfigChooser(true);
+		}
+		if (mEGLContextFactory == null) {
+			mEGLContextFactory = new DefaultContextFactory();
+		}
+		if (mEGLWindowSurfaceFactory == null) {
+			mEGLWindowSurfaceFactory = new DefaultWindowSurfaceFactory();
+		}
+		mRenderer = renderer;
+		mGLThread = new GLThread(mThisWeakRef);
+		mGLThread.start();
+	}
+
+	/**
+	 * Install a custom EGLContextFactory.
+	 * <p>If this method is
+	 * called, it must be called before {@link #setRenderer(Renderer)}
+	 * is called.
+	 * <p>
+	 * If this method is not called, then by default
+	 * a context will be created with no shared context and
+	 * with a null attribute list.
+	 */
+	public void setEGLContextFactory(EGLContextFactory factory) {
+		checkRenderThreadState();
+		mEGLContextFactory = factory;
+	}
+
+	/**
+	 * Install a custom EGLWindowSurfaceFactory.
+	 * <p>If this method is
+	 * called, it must be called before {@link #setRenderer(Renderer)}
+	 * is called.
+	 * <p>
+	 * If this method is not called, then by default
+	 * a window surface will be created with a null attribute list.
+	 */
+	public void setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory factory) {
+		checkRenderThreadState();
+		mEGLWindowSurfaceFactory = factory;
+	}
+
+	/**
+	 * Install a custom EGLConfigChooser.
+	 * <p>If this method is
+	 * called, it must be called before {@link #setRenderer(Renderer)}
+	 * is called.
+	 * <p>
+	 * If no setEGLConfigChooser method is called, then by default the
+	 * view will choose an EGLConfig that is compatible with the current
+	 * android.view.Surface, with a depth buffer depth of
+	 * at least 16 bits.
+	 * @param configChooser
+	 */
+	public void setEGLConfigChooser(EGLConfigChooser configChooser) {
+		checkRenderThreadState();
+		mEGLConfigChooser = configChooser;
+	}
+
+	/**
+	 * Install a config chooser which will choose a config
+	 * as close to 16-bit RGB as possible, with or without an optional depth
+	 * buffer as close to 16-bits as possible.
+	 * <p>If this method is
+	 * called, it must be called before {@link #setRenderer(Renderer)}
+	 * is called.
+	 * <p>
+	 * If no setEGLConfigChooser method is called, then by default the
+	 * view will choose an RGB_888 surface with a depth buffer depth of
+	 * at least 16 bits.
+	 *
+	 * @param needDepth
+	 */
+	public void setEGLConfigChooser(boolean needDepth) {
+		setEGLConfigChooser(new SimpleEGLConfigChooser(needDepth));
+	}
+
+	/**
+	 * Install a config chooser which will choose a config
+	 * with at least the specified depthSize and stencilSize,
+	 * and exactly the specified redSize, greenSize, blueSize and alphaSize.
+	 * <p>If this method is
+	 * called, it must be called before {@link #setRenderer(Renderer)}
+	 * is called.
+	 * <p>
+	 * If no setEGLConfigChooser method is called, then by default the
+	 * view will choose an RGB_888 surface with a depth buffer depth of
+	 * at least 16 bits.
+	 *
+	 */
+	public void setEGLConfigChooser(int redSize, int greenSize, int blueSize,
+									int alphaSize, int depthSize, int stencilSize) {
+		setEGLConfigChooser(new ComponentSizeChooser(redSize, greenSize,
+				blueSize, alphaSize, depthSize, stencilSize));
+	}
+
+	/**
+	 * Inform the default EGLContextFactory and default EGLConfigChooser
+	 * which EGLContext client version to pick.
+	 * <p>Use this method to create an OpenGL ES 2.0-compatible context.
+	 * Example:
+	 * <pre class="prettyprint">
+	 *     public MyView(Context context) {
+	 *         super(context);
+	 *         setEGLContextClientVersion(2); // Pick an OpenGL ES 2.0 context.
+	 *         setRenderer(new MyRenderer());
+	 *     }
+	 * </pre>
+	 * <p>Note: Activities which require OpenGL ES 2.0 should indicate this by
+	 * setting @lt;uses-feature android:glEsVersion="0x00020000" /> in the activity's
+	 * AndroidManifest.xml file.
+	 * <p>If this method is called, it must be called before {@link #setRenderer(Renderer)}
+	 * is called.
+	 * <p>This method only affects the behavior of the default EGLContexFactory and the
+	 * default EGLConfigChooser. If
+	 * {@link #setEGLContextFactory(EGLContextFactory)} has been called, then the supplied
+	 * EGLContextFactory is responsible for creating an OpenGL ES 2.0-compatible context.
+	 * If
+	 * {@link #setEGLConfigChooser(EGLConfigChooser)} has been called, then the supplied
+	 * EGLConfigChooser is responsible for choosing an OpenGL ES 2.0-compatible config.
+	 * @param version The EGLContext client version to choose. Use 2 for OpenGL ES 2.0
+	 */
+	public void setEGLContextClientVersion(int version) {
+		checkRenderThreadState();
+		mEGLContextClientVersion = version;
+	}
+
+	/**
+	 * Set the rendering mode. When renderMode is
+	 * RENDERMODE_CONTINUOUSLY, the renderer is called
+	 * repeatedly to re-render the scene. When renderMode
+	 * is RENDERMODE_WHEN_DIRTY, the renderer only rendered when the surface
+	 * is created, or when {@link #requestRender} is called. Defaults to RENDERMODE_CONTINUOUSLY.
+	 * <p>
+	 * Using RENDERMODE_WHEN_DIRTY can improve battery life and overall system performance
+	 * by allowing the GPU and CPU to idle when the view does not need to be updated.
+	 * <p>
+	 * This method can only be called after {@link #setRenderer(Renderer)}
+	 *
+	 * @param renderMode one of the RENDERMODE_X constants
+	 * @see #RENDERMODE_CONTINUOUSLY
+	 * @see #RENDERMODE_WHEN_DIRTY
+	 */
+	public void setRenderMode(int renderMode) {
+		mGLThread.setRenderMode(renderMode);
+	}
+
+	/**
+	 * Get the current rendering mode. May be called
+	 * from any thread. Must not be called before a renderer has been set.
+	 * @return the current rendering mode.
+	 * @see #RENDERMODE_CONTINUOUSLY
+	 * @see #RENDERMODE_WHEN_DIRTY
+	 */
+	public int getRenderMode() {
+		return mGLThread.getRenderMode();
+	}
+
+	/**
+	 * Request that the renderer render a frame.
+	 * This method is typically used when the render mode has been set to
+	 * {@link #RENDERMODE_WHEN_DIRTY}, so that frames are only rendered on demand.
+	 * May be called
+	 * from any thread. Must not be called before a renderer has been set.
+	 */
+	public void requestRender() {
+		mGLThread.requestRender();
+	}
+
+	/**
+	 * This method is part of the SurfaceHolder.Callback interface, and is
+	 * not normally called or subclassed by clients of GLSurfaceView.
+	 */
+	public void surfaceCreated(SurfaceHolder holder) {
+		mGLThread.surfaceCreated();
+	}
+
+	/**
+	 * This method is part of the SurfaceHolder.Callback interface, and is
+	 * not normally called or subclassed by clients of GLSurfaceView.
+	 */
+	public void surfaceDestroyed(SurfaceHolder holder) {
+		// Surface will be destroyed when we return
+		mGLThread.surfaceDestroyed();
+	}
+
+	/**
+	 * This method is part of the SurfaceHolder.Callback interface, and is
+	 * not normally called or subclassed by clients of GLSurfaceView.
+	 */
+	public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
+		mGLThread.onWindowResize(w, h);
+	}
+
+	/**
+	 * This method is part of the SurfaceHolder.Callback2 interface, and is
+	 * not normally called or subclassed by clients of GLSurfaceView.
+	 */
+	@Override
+	public void surfaceRedrawNeededAsync(SurfaceHolder holder, Runnable finishDrawing) {
+		if (mGLThread != null) {
+			mGLThread.requestRenderAndNotify(finishDrawing);
+		}
+	}
+
+	/**
+	 * This method is part of the SurfaceHolder.Callback2 interface, and is
+	 * not normally called or subclassed by clients of GLSurfaceView.
+	 */
+	@Deprecated
+	@Override
+	public void surfaceRedrawNeeded(SurfaceHolder holder) {
+		// Since we are part of the framework we know only surfaceRedrawNeededAsync
+		// will be called.
+	}
+
+
+	/**
+	 * Pause the rendering thread, optionally tearing down the EGL context
+	 * depending upon the value of {@link #setPreserveEGLContextOnPause(boolean)}.
+	 *
+	 * This method should be called when it is no longer desirable for the
+	 * GLSurfaceView to continue rendering, such as in response to
+	 * {@link android.app.Activity#onStop Activity.onStop}.
+	 *
+	 * Must not be called before a renderer has been set.
+	 */
+	public void onPause() {
+		mGLThread.onPause();
+	}
+
+	/**
+	 * Resumes the rendering thread, re-creating the OpenGL context if necessary. It
+	 * is the counterpart to {@link #onPause()}.
+	 *
+	 * This method should typically be called in
+	 * {@link android.app.Activity#onStart Activity.onStart}.
+	 *
+	 * Must not be called before a renderer has been set.
+	 */
+	public void onResume() {
+		mGLThread.onResume();
+	}
+
+	/**
+	 * Queue a runnable to be run on the GL rendering thread. This can be used
+	 * to communicate with the Renderer on the rendering thread.
+	 * Must not be called before a renderer has been set.
+	 * @param r the runnable to be run on the GL rendering thread.
+	 */
+	public void queueEvent(Runnable r) {
+		mGLThread.queueEvent(r);
+	}
+
+	/**
+	 * This method is used as part of the View class and is not normally
+	 * called or subclassed by clients of GLSurfaceView.
+	 */
+	@Override
+	protected void onAttachedToWindow() {
+		super.onAttachedToWindow();
+		if (LOG_ATTACH_DETACH) {
+			Log.d(TAG, "onAttachedToWindow reattach =" + mDetached);
+		}
+		if (mDetached && (mRenderer != null)) {
+			int renderMode = RENDERMODE_CONTINUOUSLY;
+			if (mGLThread != null) {
+				renderMode = mGLThread.getRenderMode();
+			}
+			mGLThread = new GLThread(mThisWeakRef);
+			if (renderMode != RENDERMODE_CONTINUOUSLY) {
+				mGLThread.setRenderMode(renderMode);
+			}
+			mGLThread.start();
+		}
+		mDetached = false;
+	}
+
+	@Override
+	protected void onDetachedFromWindow() {
+		if (LOG_ATTACH_DETACH) {
+			Log.d(TAG, "onDetachedFromWindow");
+		}
+		if (mGLThread != null) {
+			mGLThread.requestExitAndWait();
+		}
+		mDetached = true;
+		super.onDetachedFromWindow();
+	}
+
+	// ----------------------------------------------------------------------
+
+	/**
+	 * An interface used to wrap a GL interface.
+	 * <p>Typically
+	 * used for implementing debugging and tracing on top of the default
+	 * GL interface. You would typically use this by creating your own class
+	 * that implemented all the GL methods by delegating to another GL instance.
+	 * Then you could add your own behavior before or after calling the
+	 * delegate. All the GLWrapper would do was instantiate and return the
+	 * wrapper GL instance:
+	 * <pre class="prettyprint">
+	 * class MyGLWrapper implements GLWrapper {
+	 *     GL wrap(GL gl) {
+	 *         return new MyGLImplementation(gl);
+	 *     }
+	 *     static class MyGLImplementation implements GL,GL10,GL11,... {
+	 *         ...
+	 *     }
+	 * }
+	 * </pre>
+	 * @see #setGLWrapper(GLWrapper)
+	 */
+	public interface GLWrapper {
+		/**
+		 * Wraps a gl interface in another gl interface.
+		 * @param gl a GL interface that is to be wrapped.
+		 * @return either the input argument or another GL object that wraps the input argument.
+		 */
+		GL wrap(GL gl);
+	}
+
+	/**
+	 * A generic renderer interface.
+	 * <p>
+	 * The renderer is responsible for making OpenGL calls to render a frame.
+	 * <p>
+	 * GLSurfaceView clients typically create their own classes that implement
+	 * this interface, and then call {@link GLSurfaceView#setRenderer} to
+	 * register the renderer with the GLSurfaceView.
+	 * <p>
+	 *
+	 * <div class="special reference">
+	 * <h3>Developer Guides</h3>
+	 * <p>For more information about how to use OpenGL, read the
+	 * <a href="{@docRoot}guide/topics/graphics/opengl.html">OpenGL</a> developer guide.</p>
+	 * </div>
+	 *
+	 * <h3>Threading</h3>
+	 * The renderer will be called on a separate thread, so that rendering
+	 * performance is decoupled from the UI thread. Clients typically need to
+	 * communicate with the renderer from the UI thread, because that's where
+	 * input events are received. Clients can communicate using any of the
+	 * standard Java techniques for cross-thread communication, or they can
+	 * use the {@link GLSurfaceView#queueEvent(Runnable)} convenience method.
+	 * <p>
+	 * <h3>EGL Context Lost</h3>
+	 * There are situations where the EGL rendering context will be lost. This
+	 * typically happens when device wakes up after going to sleep. When
+	 * the EGL context is lost, all OpenGL resources (such as textures) that are
+	 * associated with that context will be automatically deleted. In order to
+	 * keep rendering correctly, a renderer must recreate any lost resources
+	 * that it still needs. The {@link #onSurfaceCreated(GL10, EGLConfig)} method
+	 * is a convenient place to do this.
+	 *
+	 *
+	 * @see #setRenderer(Renderer)
+	 */
+	public interface Renderer {
+		/**
+		 * Called when the surface is created or recreated.
+		 * <p>
+		 * Called when the rendering thread
+		 * starts and whenever the EGL context is lost. The EGL context will typically
+		 * be lost when the Android device awakes after going to sleep.
+		 * <p>
+		 * Since this method is called at the beginning of rendering, as well as
+		 * every time the EGL context is lost, this method is a convenient place to put
+		 * code to create resources that need to be created when the rendering
+		 * starts, and that need to be recreated when the EGL context is lost.
+		 * Textures are an example of a resource that you might want to create
+		 * here.
+		 * <p>
+		 * Note that when the EGL context is lost, all OpenGL resources associated
+		 * with that context will be automatically deleted. You do not need to call
+		 * the corresponding "glDelete" methods such as glDeleteTextures to
+		 * manually delete these lost resources.
+		 * <p>
+		 * @param gl the GL interface. Use <code>instanceof</code> to
+		 * test if the interface supports GL11 or higher interfaces.
+		 * @param config the EGLConfig of the created surface. Can be used
+		 * to create matching pbuffers.
+		 */
+		void onSurfaceCreated(GL10 gl, EGLConfig config);
+
+		/**
+		 * Called when the surface changed size.
+		 * <p>
+		 * Called after the surface is created and whenever
+		 * the OpenGL ES surface size changes.
+		 * <p>
+		 * Typically you will set your viewport here. If your camera
+		 * is fixed then you could also set your projection matrix here:
+		 * <pre class="prettyprint">
+		 * void onSurfaceChanged(GL10 gl, int width, int height) {
+		 *     gl.glViewport(0, 0, width, height);
+		 *     // for a fixed camera, set the projection too
+		 *     float ratio = (float) width / height;
+		 *     gl.glMatrixMode(GL10.GL_PROJECTION);
+		 *     gl.glLoadIdentity();
+		 *     gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
+		 * }
+		 * </pre>
+		 * @param gl the GL interface. Use <code>instanceof</code> to
+		 * test if the interface supports GL11 or higher interfaces.
+		 * @param width
+		 * @param height
+		 */
+		void onSurfaceChanged(GL10 gl, int width, int height);
+
+		// -- GODOT start --
+		/**
+		 * Called to draw the current frame.
+		 * <p>
+		 * This method is responsible for drawing the current frame.
+		 * <p>
+		 * The implementation of this method typically looks like this:
+		 * <pre class="prettyprint">
+		 * boolean onDrawFrame(GL10 gl) {
+		 *     gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
+		 *     //... other gl calls to render the scene ...
+		 *     return true;
+		 * }
+		 * </pre>
+		 * @param gl the GL interface. Use <code>instanceof</code> to
+		 * test if the interface supports GL11 or higher interfaces.
+		 *
+		 * @return true if the buffers should be swapped, false otherwise.
+		 */
+		boolean onDrawFrame(GL10 gl);
+		// -- GODOT end --
+	}
+
+	/**
+	 * An interface for customizing the eglCreateContext and eglDestroyContext calls.
+	 * <p>
+	 * This interface must be implemented by clients wishing to call
+	 * {@link GLSurfaceView#setEGLContextFactory(EGLContextFactory)}
+	 */
+	public interface EGLContextFactory {
+		EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig eglConfig);
+		void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context);
+	}
+
+	private class DefaultContextFactory implements EGLContextFactory {
+		private int EGL_CONTEXT_CLIENT_VERSION = 0x3098;
+
+		public EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig config) {
+			int[] attrib_list = {EGL_CONTEXT_CLIENT_VERSION, mEGLContextClientVersion,
+					EGL10.EGL_NONE };
+
+			return egl.eglCreateContext(display, config, EGL10.EGL_NO_CONTEXT,
+					mEGLContextClientVersion != 0 ? attrib_list : null);
+		}
+
+		public void destroyContext(EGL10 egl, EGLDisplay display,
+								   EGLContext context) {
+			if (!egl.eglDestroyContext(display, context)) {
+				Log.e("DefaultContextFactory", "display:" + display + " context: " + context);
+				if (LOG_THREADS) {
+					Log.i("DefaultContextFactory", "tid=" + Thread.currentThread().getId());
+				}
+				EglHelper.throwEglException("eglDestroyContex", egl.eglGetError());
+			}
+		}
+	}
+
+	/**
+	 * An interface for customizing the eglCreateWindowSurface and eglDestroySurface calls.
+	 * <p>
+	 * This interface must be implemented by clients wishing to call
+	 * {@link GLSurfaceView#setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory)}
+	 */
+	public interface EGLWindowSurfaceFactory {
+		/**
+		 *  @return null if the surface cannot be constructed.
+		 */
+		EGLSurface createWindowSurface(EGL10 egl, EGLDisplay display, EGLConfig config,
+									   Object nativeWindow);
+		void destroySurface(EGL10 egl, EGLDisplay display, EGLSurface surface);
+	}
+
+	private static class DefaultWindowSurfaceFactory implements EGLWindowSurfaceFactory {
+
+		public EGLSurface createWindowSurface(EGL10 egl, EGLDisplay display,
+											  EGLConfig config, Object nativeWindow) {
+			EGLSurface result = null;
+			try {
+				result = egl.eglCreateWindowSurface(display, config, nativeWindow, null);
+			} catch (IllegalArgumentException e) {
+				// This exception indicates that the surface flinger surface
+				// is not valid. This can happen if the surface flinger surface has
+				// been torn down, but the application has not yet been
+				// notified via SurfaceHolder.Callback.surfaceDestroyed.
+				// In theory the application should be notified first,
+				// but in practice sometimes it is not. See b/4588890
+				Log.e(TAG, "eglCreateWindowSurface", e);
+			}
+			return result;
+		}
+
+		public void destroySurface(EGL10 egl, EGLDisplay display,
+								   EGLSurface surface) {
+			egl.eglDestroySurface(display, surface);
+		}
+	}
+
+	/**
+	 * An interface for choosing an EGLConfig configuration from a list of
+	 * potential configurations.
+	 * <p>
+	 * This interface must be implemented by clients wishing to call
+	 * {@link GLSurfaceView#setEGLConfigChooser(EGLConfigChooser)}
+	 */
+	public interface EGLConfigChooser {
+		/**
+		 * Choose a configuration from the list. Implementors typically
+		 * implement this method by calling
+		 * {@link EGL10#eglChooseConfig} and iterating through the results. Please consult the
+		 * EGL specification available from The Khronos Group to learn how to call eglChooseConfig.
+		 * @param egl the EGL10 for the current display.
+		 * @param display the current display.
+		 * @return the chosen configuration.
+		 */
+		EGLConfig chooseConfig(EGL10 egl, EGLDisplay display);
+	}
+
+	private abstract class BaseConfigChooser
+			implements EGLConfigChooser {
+		public BaseConfigChooser(int[] configSpec) {
+			mConfigSpec = filterConfigSpec(configSpec);
+		}
+
+		public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {
+			int[] num_config = new int[1];
+			if (!egl.eglChooseConfig(display, mConfigSpec, null, 0,
+					num_config)) {
+				throw new IllegalArgumentException("eglChooseConfig failed");
+			}
+
+			int numConfigs = num_config[0];
+
+			if (numConfigs <= 0) {
+				throw new IllegalArgumentException(
+						"No configs match configSpec");
+			}
+
+			EGLConfig[] configs = new EGLConfig[numConfigs];
+			if (!egl.eglChooseConfig(display, mConfigSpec, configs, numConfigs,
+					num_config)) {
+				throw new IllegalArgumentException("eglChooseConfig#2 failed");
+			}
+			EGLConfig config = chooseConfig(egl, display, configs);
+			if (config == null) {
+				throw new IllegalArgumentException("No config chosen");
+			}
+			return config;
+		}
+
+		abstract EGLConfig chooseConfig(EGL10 egl, EGLDisplay display,
+										EGLConfig[] configs);
+
+		protected int[] mConfigSpec;
+
+		private int[] filterConfigSpec(int[] configSpec) {
+			if (mEGLContextClientVersion != 2 && mEGLContextClientVersion != 3) {
+				return configSpec;
+			}
+			/* We know none of the subclasses define EGL_RENDERABLE_TYPE.
+			 * And we know the configSpec is well formed.
+			 */
+			int len = configSpec.length;
+			int[] newConfigSpec = new int[len + 2];
+			System.arraycopy(configSpec, 0, newConfigSpec, 0, len-1);
+			newConfigSpec[len-1] = EGL10.EGL_RENDERABLE_TYPE;
+			if (mEGLContextClientVersion == 2) {
+				newConfigSpec[len] = EGL14.EGL_OPENGL_ES2_BIT;  /* EGL_OPENGL_ES2_BIT */
+			} else {
+				newConfigSpec[len] = EGLExt.EGL_OPENGL_ES3_BIT_KHR; /* EGL_OPENGL_ES3_BIT_KHR */
+			}
+			newConfigSpec[len+1] = EGL10.EGL_NONE;
+			return newConfigSpec;
+		}
+	}
+
+	/**
+	 * Choose a configuration with exactly the specified r,g,b,a sizes,
+	 * and at least the specified depth and stencil sizes.
+	 */
+	private class ComponentSizeChooser extends BaseConfigChooser {
+		public ComponentSizeChooser(int redSize, int greenSize, int blueSize,
+									int alphaSize, int depthSize, int stencilSize) {
+			super(new int[] {
+					EGL10.EGL_RED_SIZE, redSize,
+					EGL10.EGL_GREEN_SIZE, greenSize,
+					EGL10.EGL_BLUE_SIZE, blueSize,
+					EGL10.EGL_ALPHA_SIZE, alphaSize,
+					EGL10.EGL_DEPTH_SIZE, depthSize,
+					EGL10.EGL_STENCIL_SIZE, stencilSize,
+					EGL10.EGL_NONE});
+			mValue = new int[1];
+			mRedSize = redSize;
+			mGreenSize = greenSize;
+			mBlueSize = blueSize;
+			mAlphaSize = alphaSize;
+			mDepthSize = depthSize;
+			mStencilSize = stencilSize;
+		}
+
+		@Override
+		public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display,
+									  EGLConfig[] configs) {
+			for (EGLConfig config : configs) {
+				int d = findConfigAttrib(egl, display, config,
+						EGL10.EGL_DEPTH_SIZE, 0);
+				int s = findConfigAttrib(egl, display, config,
+						EGL10.EGL_STENCIL_SIZE, 0);
+				if ((d >= mDepthSize) && (s >= mStencilSize)) {
+					int r = findConfigAttrib(egl, display, config,
+							EGL10.EGL_RED_SIZE, 0);
+					int g = findConfigAttrib(egl, display, config,
+							EGL10.EGL_GREEN_SIZE, 0);
+					int b = findConfigAttrib(egl, display, config,
+							EGL10.EGL_BLUE_SIZE, 0);
+					int a = findConfigAttrib(egl, display, config,
+							EGL10.EGL_ALPHA_SIZE, 0);
+					if ((r == mRedSize) && (g == mGreenSize)
+							&& (b == mBlueSize) && (a == mAlphaSize)) {
+						return config;
+					}
+				}
+			}
+			return null;
+		}
+
+		private int findConfigAttrib(EGL10 egl, EGLDisplay display,
+									 EGLConfig config, int attribute, int defaultValue) {
+
+			if (egl.eglGetConfigAttrib(display, config, attribute, mValue)) {
+				return mValue[0];
+			}
+			return defaultValue;
+		}
+
+		private int[] mValue;
+		// Subclasses can adjust these values:
+		protected int mRedSize;
+		protected int mGreenSize;
+		protected int mBlueSize;
+		protected int mAlphaSize;
+		protected int mDepthSize;
+		protected int mStencilSize;
+	}
+
+	/**
+	 * This class will choose a RGB_888 surface with
+	 * or without a depth buffer.
+	 *
+	 */
+	private class SimpleEGLConfigChooser extends ComponentSizeChooser {
+		public SimpleEGLConfigChooser(boolean withDepthBuffer) {
+			super(8, 8, 8, 0, withDepthBuffer ? 16 : 0, 0);
+		}
+	}
+
+	/**
+	 * An EGL helper class.
+	 */
+
+	private static class EglHelper {
+		public EglHelper(WeakReference<GLSurfaceView> glSurfaceViewWeakRef) {
+			mGLSurfaceViewWeakRef = glSurfaceViewWeakRef;
+		}
+
+		/**
+		 * Initialize EGL for a given configuration spec.
+		 */
+		public void start() {
+			if (LOG_EGL) {
+				Log.w("EglHelper", "start() tid=" + Thread.currentThread().getId());
+			}
+			/*
+			 * Get an EGL instance
+			 */
+			mEgl = (EGL10) EGLContext.getEGL();
+
+			/*
+			 * Get to the default display.
+			 */
+			mEglDisplay = mEgl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);
+
+			if (mEglDisplay == EGL10.EGL_NO_DISPLAY) {
+				throw new RuntimeException("eglGetDisplay failed");
+			}
+
+			/*
+			 * We can now initialize EGL for that display
+			 */
+			int[] version = new int[2];
+			if(!mEgl.eglInitialize(mEglDisplay, version)) {
+				throw new RuntimeException("eglInitialize failed");
+			}
+			GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+			if (view == null) {
+				mEglConfig = null;
+				mEglContext = null;
+			} else {
+				mEglConfig = view.mEGLConfigChooser.chooseConfig(mEgl, mEglDisplay);
+
+				/*
+				 * Create an EGL context. We want to do this as rarely as we can, because an
+				 * EGL context is a somewhat heavy object.
+				 */
+				mEglContext = view.mEGLContextFactory.createContext(mEgl, mEglDisplay, mEglConfig);
+			}
+			if (mEglContext == null || mEglContext == EGL10.EGL_NO_CONTEXT) {
+				mEglContext = null;
+				throwEglException("createContext");
+			}
+			if (LOG_EGL) {
+				Log.w("EglHelper", "createContext " + mEglContext + " tid=" + Thread.currentThread().getId());
+			}
+
+			mEglSurface = null;
+		}
+
+		/**
+		 * Create an egl surface for the current SurfaceHolder surface. If a surface
+		 * already exists, destroy it before creating the new surface.
+		 *
+		 * @return true if the surface was created successfully.
+		 */
+		public boolean createSurface() {
+			if (LOG_EGL) {
+				Log.w("EglHelper", "createSurface()  tid=" + Thread.currentThread().getId());
+			}
+			/*
+			 * Check preconditions.
+			 */
+			if (mEgl == null) {
+				throw new RuntimeException("egl not initialized");
+			}
+			if (mEglDisplay == null) {
+				throw new RuntimeException("eglDisplay not initialized");
+			}
+			if (mEglConfig == null) {
+				throw new RuntimeException("mEglConfig not initialized");
+			}
+
+			/*
+			 *  The window size has changed, so we need to create a new
+			 *  surface.
+			 */
+			destroySurfaceImp();
+
+			/*
+			 * Create an EGL surface we can render into.
+			 */
+			GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+			if (view != null) {
+				mEglSurface = view.mEGLWindowSurfaceFactory.createWindowSurface(mEgl,
+						mEglDisplay, mEglConfig, view.getHolder());
+			} else {
+				mEglSurface = null;
+			}
+
+			if (mEglSurface == null || mEglSurface == EGL10.EGL_NO_SURFACE) {
+				int error = mEgl.eglGetError();
+				if (error == EGL10.EGL_BAD_NATIVE_WINDOW) {
+					Log.e("EglHelper", "createWindowSurface returned EGL_BAD_NATIVE_WINDOW.");
+				}
+				return false;
+			}
+
+			/*
+			 * Before we can issue GL commands, we need to make sure
+			 * the context is current and bound to a surface.
+			 */
+			if (!mEgl.eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext)) {
+				/*
+				 * Could not make the context current, probably because the underlying
+				 * SurfaceView surface has been destroyed.
+				 */
+				logEglErrorAsWarning("EGLHelper", "eglMakeCurrent", mEgl.eglGetError());
+				return false;
+			}
+
+			return true;
+		}
+
+		/**
+		 * Create a GL object for the current EGL context.
+		 * @return
+		 */
+		GL createGL() {
+
+			GL gl = mEglContext.getGL();
+			GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+			if (view != null) {
+				if (view.mGLWrapper != null) {
+					gl = view.mGLWrapper.wrap(gl);
+				}
+
+				if ((view.mDebugFlags & (DEBUG_CHECK_GL_ERROR | DEBUG_LOG_GL_CALLS)) != 0) {
+					int configFlags = 0;
+					Writer log = null;
+					if ((view.mDebugFlags & DEBUG_CHECK_GL_ERROR) != 0) {
+						configFlags |= GLDebugHelper.CONFIG_CHECK_GL_ERROR;
+					}
+					if ((view.mDebugFlags & DEBUG_LOG_GL_CALLS) != 0) {
+						log = new LogWriter();
+					}
+					gl = GLDebugHelper.wrap(gl, configFlags, log);
+				}
+			}
+			return gl;
+		}
+
+		/**
+		 * Display the current render surface.
+		 * @return the EGL error code from eglSwapBuffers.
+		 */
+		public int swap() {
+			if (! mEgl.eglSwapBuffers(mEglDisplay, mEglSurface)) {
+				return mEgl.eglGetError();
+			}
+			return EGL10.EGL_SUCCESS;
+		}
+
+		public void destroySurface() {
+			if (LOG_EGL) {
+				Log.w("EglHelper", "destroySurface()  tid=" + Thread.currentThread().getId());
+			}
+			destroySurfaceImp();
+		}
+
+		private void destroySurfaceImp() {
+			if (mEglSurface != null && mEglSurface != EGL10.EGL_NO_SURFACE) {
+				mEgl.eglMakeCurrent(mEglDisplay, EGL10.EGL_NO_SURFACE,
+						EGL10.EGL_NO_SURFACE,
+						EGL10.EGL_NO_CONTEXT);
+				GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+				if (view != null) {
+					view.mEGLWindowSurfaceFactory.destroySurface(mEgl, mEglDisplay, mEglSurface);
+				}
+				mEglSurface = null;
+			}
+		}
+
+		public void finish() {
+			if (LOG_EGL) {
+				Log.w("EglHelper", "finish() tid=" + Thread.currentThread().getId());
+			}
+			if (mEglContext != null) {
+				GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+				if (view != null) {
+					view.mEGLContextFactory.destroyContext(mEgl, mEglDisplay, mEglContext);
+				}
+				mEglContext = null;
+			}
+			if (mEglDisplay != null) {
+				mEgl.eglTerminate(mEglDisplay);
+				mEglDisplay = null;
+			}
+		}
+
+		private void throwEglException(String function) {
+			throwEglException(function, mEgl.eglGetError());
+		}
+
+		public static void throwEglException(String function, int error) {
+			String message = formatEglError(function, error);
+			if (LOG_THREADS) {
+				Log.e("EglHelper", "throwEglException tid=" + Thread.currentThread().getId() + " "
+						+ message);
+			}
+			throw new RuntimeException(message);
+		}
+
+		public static void logEglErrorAsWarning(String tag, String function, int error) {
+			Log.w(tag, formatEglError(function, error));
+		}
+
+		public static String formatEglError(String function, int error) {
+			return function + " failed: " + EGLLogWrapper.getErrorString(error);
+		}
+
+		private WeakReference<GLSurfaceView> mGLSurfaceViewWeakRef;
+		EGL10 mEgl;
+		EGLDisplay mEglDisplay;
+		EGLSurface mEglSurface;
+		EGLConfig mEglConfig;
+		EGLContext mEglContext;
+
+	}
+
+	/**
+	 * A generic GL Thread. Takes care of initializing EGL and GL. Delegates
+	 * to a Renderer instance to do the actual drawing. Can be configured to
+	 * render continuously or on request.
+	 *
+	 * All potentially blocking synchronization is done through the
+	 * sGLThreadManager object. This avoids multiple-lock ordering issues.
+	 *
+	 */
+	static class GLThread extends Thread {
+		GLThread(WeakReference<GLSurfaceView> glSurfaceViewWeakRef) {
+			super();
+			mWidth = 0;
+			mHeight = 0;
+			mRequestRender = true;
+			mRenderMode = RENDERMODE_CONTINUOUSLY;
+			mWantRenderNotification = false;
+			mGLSurfaceViewWeakRef = glSurfaceViewWeakRef;
+		}
+
+		@Override
+		public void run() {
+			setName("GLThread " + getId());
+			if (LOG_THREADS) {
+				Log.i("GLThread", "starting tid=" + getId());
+			}
+
+			try {
+				guardedRun();
+			} catch (InterruptedException e) {
+				// fall thru and exit normally
+			} finally {
+				sGLThreadManager.threadExiting(this);
+			}
+		}
+
+		/*
+		 * This private method should only be called inside a
+		 * synchronized(sGLThreadManager) block.
+		 */
+		private void stopEglSurfaceLocked() {
+			if (mHaveEglSurface) {
+				mHaveEglSurface = false;
+				mEglHelper.destroySurface();
+			}
+		}
+
+		/*
+		 * This private method should only be called inside a
+		 * synchronized(sGLThreadManager) block.
+		 */
+		private void stopEglContextLocked() {
+			if (mHaveEglContext) {
+				mEglHelper.finish();
+				mHaveEglContext = false;
+				sGLThreadManager.releaseEglContextLocked(this);
+			}
+		}
+		private void guardedRun() throws InterruptedException {
+			mEglHelper = new EglHelper(mGLSurfaceViewWeakRef);
+			mHaveEglContext = false;
+			mHaveEglSurface = false;
+			mWantRenderNotification = false;
+
+			try {
+				GL10 gl = null;
+				boolean createEglContext = false;
+				boolean createEglSurface = false;
+				boolean createGlInterface = false;
+				boolean lostEglContext = false;
+				boolean sizeChanged = false;
+				boolean wantRenderNotification = false;
+				boolean doRenderNotification = false;
+				boolean askedToReleaseEglContext = false;
+				int w = 0;
+				int h = 0;
+				Runnable event = null;
+				Runnable finishDrawingRunnable = null;
+
+				while (true) {
+					synchronized (sGLThreadManager) {
+						while (true) {
+							if (mShouldExit) {
+								return;
+							}
+
+							if (! mEventQueue.isEmpty()) {
+								event = mEventQueue.remove(0);
+								break;
+							}
+
+							// Update the pause state.
+							boolean pausing = false;
+							if (mPaused != mRequestPaused) {
+								pausing = mRequestPaused;
+								mPaused = mRequestPaused;
+								sGLThreadManager.notifyAll();
+								if (LOG_PAUSE_RESUME) {
+									Log.i("GLThread", "mPaused is now " + mPaused + " tid=" + getId());
+								}
+							}
+
+							// Do we need to give up the EGL context?
+							if (mShouldReleaseEglContext) {
+								if (LOG_SURFACE) {
+									Log.i("GLThread", "releasing EGL context because asked to tid=" + getId());
+								}
+								stopEglSurfaceLocked();
+								stopEglContextLocked();
+								mShouldReleaseEglContext = false;
+								askedToReleaseEglContext = true;
+							}
+
+							// Have we lost the EGL context?
+							if (lostEglContext) {
+								stopEglSurfaceLocked();
+								stopEglContextLocked();
+								lostEglContext = false;
+							}
+
+							// When pausing, release the EGL surface:
+							if (pausing && mHaveEglSurface) {
+								if (LOG_SURFACE) {
+									Log.i("GLThread", "releasing EGL surface because paused tid=" + getId());
+								}
+								stopEglSurfaceLocked();
+							}
+
+							// When pausing, optionally release the EGL Context:
+							if (pausing && mHaveEglContext) {
+								GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+								boolean preserveEglContextOnPause = view == null ?
+										false : view.mPreserveEGLContextOnPause;
+								if (!preserveEglContextOnPause) {
+									stopEglContextLocked();
+									if (LOG_SURFACE) {
+										Log.i("GLThread", "releasing EGL context because paused tid=" + getId());
+									}
+								}
+							}
+
+							// Have we lost the SurfaceView surface?
+							if ((! mHasSurface) && (! mWaitingForSurface)) {
+								if (LOG_SURFACE) {
+									Log.i("GLThread", "noticed surfaceView surface lost tid=" + getId());
+								}
+								if (mHaveEglSurface) {
+									stopEglSurfaceLocked();
+								}
+								mWaitingForSurface = true;
+								mSurfaceIsBad = false;
+								sGLThreadManager.notifyAll();
+							}
+
+							// Have we acquired the surface view surface?
+							if (mHasSurface && mWaitingForSurface) {
+								if (LOG_SURFACE) {
+									Log.i("GLThread", "noticed surfaceView surface acquired tid=" + getId());
+								}
+								mWaitingForSurface = false;
+								sGLThreadManager.notifyAll();
+							}
+
+							if (doRenderNotification) {
+								if (LOG_SURFACE) {
+									Log.i("GLThread", "sending render notification tid=" + getId());
+								}
+								mWantRenderNotification = false;
+								doRenderNotification = false;
+								mRenderComplete = true;
+								sGLThreadManager.notifyAll();
+							}
+
+							if (mFinishDrawingRunnable != null) {
+								finishDrawingRunnable = mFinishDrawingRunnable;
+								mFinishDrawingRunnable = null;
+							}
+
+							// Ready to draw?
+							if (readyToDraw()) {
+
+								// If we don't have an EGL context, try to acquire one.
+								if (! mHaveEglContext) {
+									if (askedToReleaseEglContext) {
+										askedToReleaseEglContext = false;
+									} else {
+										try {
+											mEglHelper.start();
+										} catch (RuntimeException t) {
+											sGLThreadManager.releaseEglContextLocked(this);
+											throw t;
+										}
+										mHaveEglContext = true;
+										createEglContext = true;
+
+										sGLThreadManager.notifyAll();
+									}
+								}
+
+								if (mHaveEglContext && !mHaveEglSurface) {
+									mHaveEglSurface = true;
+									createEglSurface = true;
+									createGlInterface = true;
+									sizeChanged = true;
+								}
+
+								if (mHaveEglSurface) {
+									if (mSizeChanged) {
+										sizeChanged = true;
+										w = mWidth;
+										h = mHeight;
+										mWantRenderNotification = true;
+										if (LOG_SURFACE) {
+											Log.i("GLThread",
+													"noticing that we want render notification tid="
+															+ getId());
+										}
+
+										// Destroy and recreate the EGL surface.
+										createEglSurface = true;
+
+										mSizeChanged = false;
+									}
+									mRequestRender = false;
+									sGLThreadManager.notifyAll();
+									if (mWantRenderNotification) {
+										wantRenderNotification = true;
+									}
+									break;
+								}
+							} else {
+								if (finishDrawingRunnable != null) {
+									Log.w(TAG, "Warning, !readyToDraw() but waiting for " +
+											"draw finished! Early reporting draw finished.");
+									finishDrawingRunnable.run();
+									finishDrawingRunnable = null;
+								}
+							}
+							// By design, this is the only place in a GLThread thread where we wait().
+							if (LOG_THREADS) {
+								Log.i("GLThread", "waiting tid=" + getId()
+										+ " mHaveEglContext: " + mHaveEglContext
+										+ " mHaveEglSurface: " + mHaveEglSurface
+										+ " mFinishedCreatingEglSurface: " + mFinishedCreatingEglSurface
+										+ " mPaused: " + mPaused
+										+ " mHasSurface: " + mHasSurface
+										+ " mSurfaceIsBad: " + mSurfaceIsBad
+										+ " mWaitingForSurface: " + mWaitingForSurface
+										+ " mWidth: " + mWidth
+										+ " mHeight: " + mHeight
+										+ " mRequestRender: " + mRequestRender
+										+ " mRenderMode: " + mRenderMode);
+							}
+							sGLThreadManager.wait();
+						}
+					} // end of synchronized(sGLThreadManager)
+
+					if (event != null) {
+						event.run();
+						event = null;
+						continue;
+					}
+
+					if (createEglSurface) {
+						if (LOG_SURFACE) {
+							Log.w("GLThread", "egl createSurface");
+						}
+						if (mEglHelper.createSurface()) {
+							synchronized(sGLThreadManager) {
+								mFinishedCreatingEglSurface = true;
+								sGLThreadManager.notifyAll();
+							}
+						} else {
+							synchronized(sGLThreadManager) {
+								mFinishedCreatingEglSurface = true;
+								mSurfaceIsBad = true;
+								sGLThreadManager.notifyAll();
+							}
+							continue;
+						}
+						createEglSurface = false;
+					}
+
+					if (createGlInterface) {
+						gl = (GL10) mEglHelper.createGL();
+
+						createGlInterface = false;
+					}
+
+					// -- GODOT start --
+					if (createEglContext) {
+						if (LOG_RENDERER) {
+							Log.w("GLThread", "onSurfaceCreated");
+						}
+						GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+						if (view != null) {
+							try {
+								view.mRenderer.onSurfaceCreated(gl, mEglHelper.mEglConfig);
+							} finally {
+							}
+						}
+						createEglContext = false;
+					}
+
+					if (sizeChanged) {
+						if (LOG_RENDERER) {
+							Log.w("GLThread", "onSurfaceChanged(" + w + ", " + h + ")");
+						}
+						GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+						if (view != null) {
+							try {
+								view.mRenderer.onSurfaceChanged(gl, w, h);
+							} finally {
+							}
+						}
+						sizeChanged = false;
+					}
+
+					boolean swapBuffers = false;
+					if (LOG_RENDERER_DRAW_FRAME) {
+						Log.w("GLThread", "onDrawFrame tid=" + getId());
+					}
+					{
+						GLSurfaceView view = mGLSurfaceViewWeakRef.get();
+						if (view != null) {
+							try {
+								swapBuffers = view.mRenderer.onDrawFrame(gl);
+								if (finishDrawingRunnable != null) {
+									finishDrawingRunnable.run();
+									finishDrawingRunnable = null;
+								}
+							} finally {}
+						}
+					}
+					if (swapBuffers) {
+						int swapError = mEglHelper.swap();
+						switch (swapError) {
+							case EGL10.EGL_SUCCESS:
+								break;
+							case EGL11.EGL_CONTEXT_LOST:
+								if (LOG_SURFACE) {
+									Log.i("GLThread", "egl context lost tid=" + getId());
+								}
+								lostEglContext = true;
+								break;
+							default:
+								// Other errors typically mean that the current surface is bad,
+								// probably because the SurfaceView surface has been destroyed,
+								// but we haven't been notified yet.
+								// Log the error to help developers understand why rendering stopped.
+								EglHelper.logEglErrorAsWarning("GLThread", "eglSwapBuffers", swapError);
+
+								synchronized (sGLThreadManager) {
+									mSurfaceIsBad = true;
+									sGLThreadManager.notifyAll();
+								}
+								break;
+						}
+					}
+					// -- GODOT end --
+
+					if (wantRenderNotification) {
+						doRenderNotification = true;
+						wantRenderNotification = false;
+					}
+				}
+
+			} finally {
+				/*
+				 * clean-up everything...
+				 */
+				synchronized (sGLThreadManager) {
+					stopEglSurfaceLocked();
+					stopEglContextLocked();
+				}
+			}
+		}
+
+		public boolean ableToDraw() {
+			return mHaveEglContext && mHaveEglSurface && readyToDraw();
+		}
+
+		private boolean readyToDraw() {
+			return (!mPaused) && mHasSurface && (!mSurfaceIsBad)
+					&& (mWidth > 0) && (mHeight > 0)
+					&& (mRequestRender || (mRenderMode == RENDERMODE_CONTINUOUSLY));
+		}
+
+		public void setRenderMode(int renderMode) {
+			if ( !((RENDERMODE_WHEN_DIRTY <= renderMode) && (renderMode <= RENDERMODE_CONTINUOUSLY)) ) {
+				throw new IllegalArgumentException("renderMode");
+			}
+			synchronized(sGLThreadManager) {
+				mRenderMode = renderMode;
+				sGLThreadManager.notifyAll();
+			}
+		}
+
+		public int getRenderMode() {
+			synchronized(sGLThreadManager) {
+				return mRenderMode;
+			}
+		}
+
+		public void requestRender() {
+			synchronized(sGLThreadManager) {
+				mRequestRender = true;
+				sGLThreadManager.notifyAll();
+			}
+		}
+
+		public void requestRenderAndNotify(Runnable finishDrawing) {
+			synchronized(sGLThreadManager) {
+				// If we are already on the GL thread, this means a client callback
+				// has caused reentrancy, for example via updating the SurfaceView parameters.
+				// We will return to the client rendering code, so here we don't need to
+				// do anything.
+				if (Thread.currentThread() == this) {
+					return;
+				}
+
+				mWantRenderNotification = true;
+				mRequestRender = true;
+				mRenderComplete = false;
+				mFinishDrawingRunnable = finishDrawing;
+
+				sGLThreadManager.notifyAll();
+			}
+		}
+
+		public void surfaceCreated() {
+			synchronized(sGLThreadManager) {
+				if (LOG_THREADS) {
+					Log.i("GLThread", "surfaceCreated tid=" + getId());
+				}
+				mHasSurface = true;
+				mFinishedCreatingEglSurface = false;
+				sGLThreadManager.notifyAll();
+				while (mWaitingForSurface
+						&& !mFinishedCreatingEglSurface
+						&& !mExited) {
+					try {
+						sGLThreadManager.wait();
+					} catch (InterruptedException e) {
+						Thread.currentThread().interrupt();
+					}
+				}
+			}
+		}
+
+		public void surfaceDestroyed() {
+			synchronized(sGLThreadManager) {
+				if (LOG_THREADS) {
+					Log.i("GLThread", "surfaceDestroyed tid=" + getId());
+				}
+				mHasSurface = false;
+				sGLThreadManager.notifyAll();
+				while((!mWaitingForSurface) && (!mExited)) {
+					try {
+						sGLThreadManager.wait();
+					} catch (InterruptedException e) {
+						Thread.currentThread().interrupt();
+					}
+				}
+			}
+		}
+
+		public void onPause() {
+			synchronized (sGLThreadManager) {
+				if (LOG_PAUSE_RESUME) {
+					Log.i("GLThread", "onPause tid=" + getId());
+				}
+				mRequestPaused = true;
+				sGLThreadManager.notifyAll();
+				while ((! mExited) && (! mPaused)) {
+					if (LOG_PAUSE_RESUME) {
+						Log.i("Main thread", "onPause waiting for mPaused.");
+					}
+					try {
+						sGLThreadManager.wait();
+					} catch (InterruptedException ex) {
+						Thread.currentThread().interrupt();
+					}
+				}
+			}
+		}
+
+		public void onResume() {
+			synchronized (sGLThreadManager) {
+				if (LOG_PAUSE_RESUME) {
+					Log.i("GLThread", "onResume tid=" + getId());
+				}
+				mRequestPaused = false;
+				mRequestRender = true;
+				mRenderComplete = false;
+				sGLThreadManager.notifyAll();
+				while ((! mExited) && mPaused && (!mRenderComplete)) {
+					if (LOG_PAUSE_RESUME) {
+						Log.i("Main thread", "onResume waiting for !mPaused.");
+					}
+					try {
+						sGLThreadManager.wait();
+					} catch (InterruptedException ex) {
+						Thread.currentThread().interrupt();
+					}
+				}
+			}
+		}
+
+		public void onWindowResize(int w, int h) {
+			synchronized (sGLThreadManager) {
+				mWidth = w;
+				mHeight = h;
+				mSizeChanged = true;
+				mRequestRender = true;
+				mRenderComplete = false;
+
+				// If we are already on the GL thread, this means a client callback
+				// has caused reentrancy, for example via updating the SurfaceView parameters.
+				// We need to process the size change eventually though and update our EGLSurface.
+				// So we set the parameters and return so they can be processed on our
+				// next iteration.
+				if (Thread.currentThread() == this) {
+					return;
+				}
+
+				sGLThreadManager.notifyAll();
+
+				// Wait for thread to react to resize and render a frame
+				while (! mExited && !mPaused && !mRenderComplete
+						&& ableToDraw()) {
+					if (LOG_SURFACE) {
+						Log.i("Main thread", "onWindowResize waiting for render complete from tid=" + getId());
+					}
+					try {
+						sGLThreadManager.wait();
+					} catch (InterruptedException ex) {
+						Thread.currentThread().interrupt();
+					}
+				}
+			}
+		}
+
+		public void requestExitAndWait() {
+			// don't call this from GLThread thread or it is a guaranteed
+			// deadlock!
+			synchronized(sGLThreadManager) {
+				mShouldExit = true;
+				sGLThreadManager.notifyAll();
+				while (! mExited) {
+					try {
+						sGLThreadManager.wait();
+					} catch (InterruptedException ex) {
+						Thread.currentThread().interrupt();
+					}
+				}
+			}
+		}
+
+		public void requestReleaseEglContextLocked() {
+			mShouldReleaseEglContext = true;
+			sGLThreadManager.notifyAll();
+		}
+
+		/**
+		 * Queue an "event" to be run on the GL rendering thread.
+		 * @param r the runnable to be run on the GL rendering thread.
+		 */
+		public void queueEvent(Runnable r) {
+			if (r == null) {
+				throw new IllegalArgumentException("r must not be null");
+			}
+			synchronized(sGLThreadManager) {
+				mEventQueue.add(r);
+				sGLThreadManager.notifyAll();
+			}
+		}
+
+		// Once the thread is started, all accesses to the following member
+		// variables are protected by the sGLThreadManager monitor
+		private boolean mShouldExit;
+		private boolean mExited;
+		private boolean mRequestPaused;
+		private boolean mPaused;
+		private boolean mHasSurface;
+		private boolean mSurfaceIsBad;
+		private boolean mWaitingForSurface;
+		private boolean mHaveEglContext;
+		private boolean mHaveEglSurface;
+		private boolean mFinishedCreatingEglSurface;
+		private boolean mShouldReleaseEglContext;
+		private int mWidth;
+		private int mHeight;
+		private int mRenderMode;
+		private boolean mRequestRender;
+		private boolean mWantRenderNotification;
+		private boolean mRenderComplete;
+		private ArrayList<Runnable> mEventQueue = new ArrayList<Runnable>();
+		private boolean mSizeChanged = true;
+		private Runnable mFinishDrawingRunnable = null;
+
+		// End of member variables protected by the sGLThreadManager monitor.
+
+		private EglHelper mEglHelper;
+
+		/**
+		 * Set once at thread construction time, nulled out when the parent view is garbage
+		 * called. This weak reference allows the GLSurfaceView to be garbage collected while
+		 * the GLThread is still alive.
+		 */
+		private WeakReference<GLSurfaceView> mGLSurfaceViewWeakRef;
+
+	}
+
+	static class LogWriter extends Writer {
+
+		@Override public void close() {
+			flushBuilder();
+		}
+
+		@Override public void flush() {
+			flushBuilder();
+		}
+
+		@Override public void write(char[] buf, int offset, int count) {
+			for(int i = 0; i < count; i++) {
+				char c = buf[offset + i];
+				if ( c == '\n') {
+					flushBuilder();
+				}
+				else {
+					mBuilder.append(c);
+				}
+			}
+		}
+
+		private void flushBuilder() {
+			if (mBuilder.length() > 0) {
+				Log.v("GLSurfaceView", mBuilder.toString());
+				mBuilder.delete(0, mBuilder.length());
+			}
+		}
+
+		private StringBuilder mBuilder = new StringBuilder();
+	}
+
+
+	private void checkRenderThreadState() {
+		if (mGLThread != null) {
+			throw new IllegalStateException(
+					"setRenderer has already been called for this instance.");
+		}
+	}
+
+	private static class GLThreadManager {
+		private static String TAG = "GLThreadManager";
+
+		public synchronized void threadExiting(GLThread thread) {
+			if (LOG_THREADS) {
+				Log.i("GLThread", "exiting tid=" +  thread.getId());
+			}
+			thread.mExited = true;
+			notifyAll();
+		}
+
+		/*
+		 * Releases the EGL context. Requires that we are already in the
+		 * sGLThreadManager monitor when this is called.
+		 */
+		public void releaseEglContextLocked(GLThread thread) {
+			notifyAll();
+		}
+	}
+
+	private static final GLThreadManager sGLThreadManager = new GLThreadManager();
+
+	private final WeakReference<GLSurfaceView> mThisWeakRef =
+			new WeakReference<GLSurfaceView>(this);
+	private GLThread mGLThread;
+	private Renderer mRenderer;
+	private boolean mDetached;
+	private EGLConfigChooser mEGLConfigChooser;
+	private EGLContextFactory mEGLContextFactory;
+	private EGLWindowSurfaceFactory mEGLWindowSurfaceFactory;
+	private GLWrapper mGLWrapper;
+	private int mDebugFlags;
+	private int mEGLContextClientVersion;
+	private boolean mPreserveEGLContextOnPause;
+}
+
diff --git a/platform/android/java/lib/src/org/godotengine/godot/GodotRenderer.java b/platform/android/java/lib/src/org/godotengine/godot/gl/GodotRenderer.java
index e3956ac459..5c4fd00f6d 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/GodotRenderer.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/gl/GodotRenderer.java
@@ -28,38 +28,38 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-package org.godotengine.godot;
+package org.godotengine.godot.gl;
 
+import org.godotengine.godot.GodotLib;
 import org.godotengine.godot.plugin.GodotPlugin;
 import org.godotengine.godot.plugin.GodotPluginRegistry;
-import org.godotengine.godot.utils.GLUtils;
-
-import android.opengl.GLSurfaceView;
 
 import javax.microedition.khronos.egl.EGLConfig;
 import javax.microedition.khronos.opengles.GL10;
 
 /**
- * Godot's renderer implementation.
+ * Godot's GL renderer implementation.
  */
-class GodotRenderer implements GLSurfaceView.Renderer {
+public class GodotRenderer implements GLSurfaceView.Renderer {
 	private final GodotPluginRegistry pluginRegistry;
 	private boolean activityJustResumed = false;
 
-	GodotRenderer() {
+	public GodotRenderer() {
 		this.pluginRegistry = GodotPluginRegistry.getPluginRegistry();
 	}
 
-	public void onDrawFrame(GL10 gl) {
+	public boolean onDrawFrame(GL10 gl) {
 		if (activityJustResumed) {
 			GodotLib.onRendererResumed();
 			activityJustResumed = false;
 		}
 
-		GodotLib.step();
+		boolean swapBuffers = GodotLib.step();
 		for (GodotPlugin plugin : pluginRegistry.getAllPlugins()) {
 			plugin.onGLDrawFrame(gl);
 		}
+
+		return swapBuffers;
 	}
 
 	public void onSurfaceChanged(GL10 gl, int width, int height) {
@@ -76,13 +76,13 @@ class GodotRenderer implements GLSurfaceView.Renderer {
 		}
 	}
 
-	void onActivityResumed() {
+	public void onActivityResumed() {
 		// We defer invoking GodotLib.onRendererResumed() until the first draw frame call.
 		// This ensures we have a valid GL context and surface when we do so.
 		activityJustResumed = true;
 	}
 
-	void onActivityPaused() {
+	public void onActivityPaused() {
 		GodotLib.onRendererPaused();
 	}
 }
diff --git a/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrConfigChooser.java b/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrConfigChooser.java
index 4c1c84affb..e35d4f5828 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrConfigChooser.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrConfigChooser.java
@@ -30,8 +30,9 @@
 
 package org.godotengine.godot.xr.ovr;
 
+import org.godotengine.godot.gl.GLSurfaceView;
+
 import android.opengl.EGLExt;
-import android.opengl.GLSurfaceView;
 
 import javax.microedition.khronos.egl.EGL10;
 import javax.microedition.khronos.egl.EGLConfig;
diff --git a/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrContextFactory.java b/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrContextFactory.java
index 2b4369b8a6..deb9c4bb1d 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrContextFactory.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrContextFactory.java
@@ -30,8 +30,9 @@
 
 package org.godotengine.godot.xr.ovr;
 
+import org.godotengine.godot.gl.GLSurfaceView;
+
 import android.opengl.EGL14;
-import android.opengl.GLSurfaceView;
 
 import javax.microedition.khronos.egl.EGL10;
 import javax.microedition.khronos.egl.EGLConfig;
diff --git a/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrWindowSurfaceFactory.java b/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrWindowSurfaceFactory.java
index fbfe0a3a75..f087b7dc74 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrWindowSurfaceFactory.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/xr/ovr/OvrWindowSurfaceFactory.java
@@ -30,7 +30,7 @@
 
 package org.godotengine.godot.xr.ovr;
 
-import android.opengl.GLSurfaceView;
+import org.godotengine.godot.gl.GLSurfaceView;
 
 import javax.microedition.khronos.egl.EGL10;
 import javax.microedition.khronos.egl.EGLConfig;
diff --git a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularConfigChooser.java b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularConfigChooser.java
index 9fde1961ea..445238b1c2 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularConfigChooser.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularConfigChooser.java
@@ -30,10 +30,9 @@
 
 package org.godotengine.godot.xr.regular;
 
+import org.godotengine.godot.gl.GLSurfaceView;
 import org.godotengine.godot.utils.GLUtils;
 
-import android.opengl.GLSurfaceView;
-
 import javax.microedition.khronos.egl.EGL10;
 import javax.microedition.khronos.egl.EGLConfig;
 import javax.microedition.khronos.egl.EGLDisplay;
diff --git a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularContextFactory.java b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularContextFactory.java
index ce1184a75c..5d62723170 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularContextFactory.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularContextFactory.java
@@ -30,9 +30,9 @@
 
 package org.godotengine.godot.xr.regular;
 
+import org.godotengine.godot.gl.GLSurfaceView;
 import org.godotengine.godot.utils.GLUtils;
 
-import android.opengl.GLSurfaceView;
 import android.util.Log;
 
 import javax.microedition.khronos.egl.EGL10;
diff --git a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularFallbackConfigChooser.java b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularFallbackConfigChooser.java
index 420dda45a0..68329c5c49 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularFallbackConfigChooser.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/xr/regular/RegularFallbackConfigChooser.java
@@ -30,8 +30,6 @@
 
 package org.godotengine.godot.xr.regular;
 
-import org.godotengine.godot.utils.GLUtils;
-
 import android.util.Log;
 
 import javax.microedition.khronos.egl.EGL10;